Medical personnel, such as practitioners, have recently found benefit in using robotic systems to perform surgical procedures. Such a robotic system typically includes a moveable arm. The movable arm has a free, distal end that can be positioned with a very high degree of accuracy. A surgical instrument is attached to the free end of the arm. The surgical instrument is designed to be applied to a surgical site.
In early robotic systems, medical personnel rigidly fixed the patient in a surgical holder thereby fixing the surgical site in a static patient coordinate system. However, recent robotic systems employ surgical holders that allow slight movements of the patient. As such, modern surgical holders do not rigidly fix the surgical site in a static patient coordinate system.
One drawback of allowing movement of the surgical site is the possibility that the surgical site is too loosely secured during autonomous operation of the robotic system. In this situation, a position control loop of the robotic system continually attempts to reach a target at the surgical site while at the same time constantly pushing the target out of reach. As a result, the surgical instrument is positioned inaccurately at the surgical site, thereby adding unnecessary delay to the surgical procedure.
As such, it is desirable to develop a robotic system which can compensate for these conditions or prevent the condition altogether.